Groundwater Model

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Groundwater Model

• An explanation of different groundwater
  situations and their effects on surrounding areas
  using a model

Designed by Kahle Toothill Edited by Holly
Longenberger
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Project Sponsors

• Pocono Northeast Resource Conservation
  Development Council
• http//www.pnercd.org
• C-SAW Program - Consortium for Scientific
  Assistance to Watersheds Program
  http//pa.water.usgs.gov/csaw/
• PA Association of Environmental Professionals
• http//www.paep.org

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Environmental Engineering and Earth Sciences
Department

• Degrees Programs
• Environmental Engineering
• (ABET Accredited BA and BS Degrees)
• Water and Wastewater Treatment, Hydrology, Air
  Quality,
• Hazardous Waste Management, Bioremediation,
  Stormwater Management, Land Reclamation
• Earth Environmental Sciences
• (BA and BS Degrees and Secondary Education
• Degree Opportunities)
• Water Quality, Soils, Geology, Geographic
  Information
• Systems (GIS), Global Positioning Systems (GPS),
• Freshwater and Marine Ecosystems, Global
  Positioning,
• Land-Use Planning, Field Training, Environmental
  Analysis

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Wilkes University Environmental Engineering and
Earth Sciences Department visit us at
http//www.wilkes.edu/pages/388.asp

• Earth Environmental Sciences
• 4-Year Programs for a
• Bachelor of Arts (BA) Degree
• Bachelor of Science (BS) Degree
• Also available
• A minor
• Secondary Education Certification (7-12)
• Elementary Education Certification (1-6)

• Environmental Engineering
• National Recognized and
• Accredited (ABET)
• Bachelor of Science (BS) Degree

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Wilkes University

• Center for Environmental Quality
• Visit for information
• http//www.water-research.net
• Laboratory Testing
• Water Quality Monitoring
• Homeowner Outreach Program
• Community and Business Outreach Programs
• Environmental and Professional Education and
  Training
• Applied Research, Product Testing and Technology
  Transfer

• Geographic Information Sciences Center
• Visit for more information
• http//www.wilkes.edu/pages/388.asp
• Academic courses
• -curriculum includes GIS, GPS, remote sensing,
  and photogrametry technologies
• Training
• -ESRI Software and Certified Trimble Pro XR GPS
  Training
• Projects
• Presentations

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Wilkes University

• Wallops Island Marine Consortium
• Wilkes is a participating member in the Wallops
  Island Marine Consortium in Virginia.
• The purpose of the consortium is to allow
  students to work at a marine field station and
  gain first hand knowledge relating to the marine
  environment and environmental science.

• Back Mountain Recreational Center Field Station
• natural laboratory dedicated to field-based
  training and research.
• a secure and permanent site for long-term
  monitoring of natural processes.
• students gain valuable field experience in
  collecting, handling and field analyzing samples
  of rock, soils, sediment, groundwater, surface
  water and vegetation.

For more details visit
http//www.wilkes.edu/pages/606.asp
http//www.wilkes.edu/pages/926.asp
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Water LevelsWater Moves from Areas of High
Pressure to Low Pressure
No Horizontal Flow
Source of water

1. Water Moves from Recharge to Discharge Zone
2. Some water lost thoughevaporation

1. No lateral water movement
2. Water is lost due to evaporation

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GroundwaterHow much do we use each day?
http//ga.water.usgs.gov/edu/wups.html
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IntroductionWater Levels- They Are Not Static !

• The water level in a system is controlled by the
  location of the groundwater recharge and
  discharge zones and the amount of water withdrawn
  or injected into the system.
• The static levels in lakes, ponds, wells, etc.
  will change in response to changes in
  precipitation, evaporation, water
  withdrawals,water injection, and groundwater
  discharge.
• Static water levels in confined aquifers respond
  to changes in barometric pressure, water
  withdrawals, surface activities, and water
  injection or recharge into the groundwater
  system.

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IntroductionWater Levels- They Are Not Static !
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Scenario 1Groundwater Comes From Nearby Sources

• The upside-down water bottle on the left of the
  model represents our water source which is
  theRecharge Zone.

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Scenario 2Water Flows From Recharge Zones to
Discharge Zones

• Recharge Zone The area where water enters the
  groundwater flow system. The direction of flow
  is downward.
• In the saturated zone - All spaces between soil
  and rock are filled with water
• In the unsaturated zone - the pore spaces are
  filled with air and water.
• Discharge Zone The area in which groundwater
  leaves the system either as a spring, stream
  flow, wetlands, direct evaporation, water
  withdrawal, or large water body (lake, ocean,
  estuary, bay, etc).

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Scenario 2Water Flows From Recharge Zones to
Discharge Zones

• Water moves from areas of high head or elevation
  to low head or lower elevation.
• The use of food coloring will help to see how the
  water moves through the system.

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Scenario 2Water Flows From Recharge Zones to
Discharge Zones

• Water moves from many zones within the model
  below, food coloring is used to show how water
  travels in a system. Typically water flows from
  high head /high elevation to a low head / lower
  elevation.

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Scenario 3Introduction to Well Pumping

• Groundwater is pumped from the ground through
  wells for use in our homes, businesses, and
  industries.
• Drilled into aquifers
• An underground layer of rock and sand that is
  saturated may contain a sufficient amount of
  water to support a single family unit with a
  sustainable yield of 1 gpm or higher.
• Pumps typically remove water from the wellbore.
  In the case of an artesian well, no pump may be
  needed to bring the water to the surface.

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Scenario 3Introduction to Well Pumping
Our pump is inserted into a well and the water
is drawn into the flask on the right.
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Scenario 4Relationship Between Groundwater
Surface Water

• Groundwater supports and feeds lakes, streams,
  wetlands, and the ocean, especially during dry
  periods as baseflow.
• Springs locations were the piezometric surface
  intersects the ground level.

The lake is filled to an elevation that is
equivalent to the water table. The arrow
(artesian well) represents a discharge from the
deeper confined aquifer.
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Scenario 5Aquifers are Not Uniform
Different types of soil, rock, gravel, and sand
make up the ground. These types of structures
hold, store, and, release different amounts of
water depending on the properties of the material.
http//ga.water.usgs.gov/edu/earthgwaquifer.html
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Scenario 6Springs Lower the Level of the Water
Table

• The Water Table
• is the top of the saturated zone.
• has many peaks and valleys in its shape due to
  the topography of the land. It fluctuates in
  response to precipitation, evapotranspiration,
  and groundwater recharge or discharge.
• the level below which the soil is saturated with
  water and head is 0 or greater. (2)

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Scenario 6Springs Change the Level of the Water
Table

• The level of the water in the pipet tip with the
  green fluid represents the piezometeric surface
  of the artesian aquifer.
• Water level is above lake level.
• At the current lake level - The removal of the
  pipet tip would cause the artesian water to be
  pumped into the lake.

Piezometeric Surface
Water Table
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Scenario 6Springs Change the Level of the Water
Table

• Water in a spring is water moving through the
  hydrologic cycle.
• Springs are sources of water high in minerals.
• Springs are vulnerable to pollution and
  contaminants just like groundwater.

http//ga.water.usgs.gov/edu/gwartesian.html
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Scenario 7The Texture of the Aquifer Affects the
Rate of Groundwater Flow.

• Aquifer
• underground units of rock, soil, and other
  unconsolidated material that can store and
  transmit water.
• may be separated by confining layers.
• Confining Layers
• layers which have fine pores that transmit water
  slowly.
• must have a permeability 2 orders of magnitude
  lower (100 x lower) than the adjacent aquifer to
  be a confining layer.
• examples could be unfractured bedrock, fine sand
  over coarse sand, and silt or clay layers.

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Scenario 7The Texture of the Aquifer Affects the
rate of Groundwater Flow.

• Under saturated conditions, the gravel layer will
  have a higher permeability.
• Water also travels through sand, silt, and, clay
  but the rate of movement is a function of the
  degree of saturation, hydraulic gradient, and
  permeability.
• Water does not move easily or readily through the
  confining layer. Water movement is a function of
  permeability (K) and hydraulic gradient (dh/dl).

Sand
Gravel layer
Confining layer
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Scenario 7The Texture of the Aquifer Affects the
rate of Groundwater Flow.

• The lower the friction between the soil
  particles, the higher the velocity of the water
  moving through it.
• Water in an aquifer takes path of least
  resistance.
• Under the same gradient and saturated conditions,
  the dye tends to move faster in the gravel
  because of the higher permeability of the
  material.

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Scenario 8Drawing Water from a Well Can
Interfere with Neighboring Wells
The pumping of this well acts as an artificial
discharge zone that influences the natural
groundwater flow, induces drawdown, and reverses
the direction of groundwater flow.
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Scenario 8Drawing Water from a Well Can
Interfere with Neighboring Wells

• The over pumping of a well or excessive
  groundwater withdrawal can cause
• The level of water in other wells to drop and the
  yield in these wells to decrease.
• Water levels in nearby surface water may drop
  and the rate of discharge from the system via
  natural processes will decrease.
• This is well interference and over-pumping can
  cause Groundwater Harvesting.

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Scenario 9Human Activities Near the SurfaceCan
Contaminate Groundwater

• Red food coloring was added to the model as a
  point source or contaminate.
• The contaminate could be lechate from a landfill,
  leakage from a septic systems,or a plume of oil
  from an old heating oil tank etc.
• Contaminates move through the unsaturated zone of
  the soil, then into the water table, and
  eventually to a discharge zone.
• Examples of possible discharge zones lake,
  stream, ocean, wetlands, water wells, and
  springs.

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Scenario 9Human Activities Near the SurfaceCan
Contaminate Groundwater
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Scenario 9Human Activities Near the SurfaceCan
Contaminate Groundwater
Contaminate
Because the shallow well was pumped, the
contamination was pulled from the shallow water
aquifer into the deeper aquifer. If the well was
not pumped the contamination would not have
contaminated this zone.
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Scenario 9Human Activities Near the SurfaceCan
Contaminate Groundwater
The initial contamination spreads quick.
It eventually spreads into wells and the lake.
The water that was spilled into the point source
eventually runs throughout the model and exists
at the discharge zone.
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Scenario 10Wells Can be Contaminated by Human
Activities at the Surface

• A well being pumped draws water into it from all
  directions- including downgradient.
• Pumping wells alters natural groundwater flow and
  can reverse the direction of flow. (What was
  downgradient is NOW upgradient).
• Point and Non-Point Contamination can influence
  groundwater quality

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Scenario 11Contaminated Groundwater May Pollute
Surface Water

• Water collecting in the lake is not clear,
  because a portion of the water is contaminated by
  a series of non-point sources of pollution.
• Baseflow The portion of streamflow which comes
  from groundwater.
• Contaminants in groundwater can be discharged
  into surface water sources (discharge zones).
  This can cause acute/chronic environmental
  impacts on terrestrial and aquatic ecosystems.

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Scenario 12Water Quality Can Vary Within an
Aquifer

• Observe the colored water contaminates.
• At first the plumes are narrow.
• Later they become wider as the water flows
  through the formation and contamination disperses
  and diffuses.
• Soon contamination plumes have widened to the
  point that there is a zone of contamination.

Zone of Contamination
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Scenario 12Water Quality Can Vary Within an
Aquifer

• MOVEMENT OF CONTAMINANTS
• Diffusion is the movement of particles (ions or
  molecules) from an area of higher concentration
  to an area of lower concentration. (3) Example A
  contaminate going into the groundwater.
• Advection a process of movement in which a
  contaminant can be transported by water
  migration.
• Degradation absorbs contaminants so they move at
  a slower rate than the water in an aquifer
  (dilution).
• Retardation pollutants tend to disassociate into
  negative and positive ions. Soil can then
  attract, absorb or repel the pollutant.

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Scenario 13Wells Can Pollute Groundwater

• Well defects
• cracks, holes, rusted casing, loose cap, eroded
  grout, lack of grouting, insufficient casing, or
  poor well construction.
• cause contaminated surface water to get into
  groundwater supply.
• state regulations exist concerning proper
  construction, maintenance, and, abandonment for
  community and non-community wells, but NOT most
  Private Wells in PA.

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Scenario 14Once Groundwater is Contaminated,
the Contamination May Persist for Long Periods
of Time

• Observe the colored water in the model. This is
  what could happen to the ground as a result of
  pollution.

• Eventually, the pollution will be flushed out
  of the model and back to a pristine state. In
  order to get it back to this condition, it could
  take hundreds to 1000s of years.

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Scenario 14Once Groundwater is Contaminated,
the Contamination May Persist for Long Periods
of Time

• Unlike the model, the environment cant eliminate
  or flush pollutants easily or quickly !
• Contaminants may move a few feet/year or less !
• Eventually contaminates will reach discharge
  zones and may be partially eliminated by natural
  processes !
• If contaminates are not removed they end up in
  sources of freshwater or the ocean!

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Scenario 14Once Groundwater is Contaminated,
the Contamination May Persist for Long Periods
of Time
http//www.egr.msu.edu/tosc/grandcal/images/contse
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http//soc.hfac.uh.edu/artman/uploads/envir02r.gif
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Conclusion

• Make smart decisions when it comes to our water
  usage.
• Dispose of Wastes Properly.
• Encourage Recycling Programs.
• Use Environmentally Safe Products (Look for Green
  Products).
• Make conscious decisions in land-use planning
  and development.
• Encourage Private Well Construction Standards and
  Proper Well Siting Guidelines.
• Get your drinking water tested on an annual
  basis.

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Project Sponsors

• Pocono Northeast Resource Conservation
  Development Council
• http//www.pnercd.org
• C-SAW Program - Consortium for Scientific
  Assistance to Watersheds Program
  http//pa.water.usgs.gov/csaw/
• PA Association of Environmental Professionals
• http//www.paep.org

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Wilkes University

• Wilkes offers a wide range of information and
  services such as
• Degree Programs in Environmental Engineering and
  Earth Environmental Sciences
• Center for Environmental Quality Water Research
  Laboratory
• Geographic Information Systems and Remote Sensing
  Center
• Professional and Continuing Training/ Education
  Opportunities
• Technological Support and Grant Partner
• Visit us at

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References

• 1. Sand-Tank Ground Water Flow Model Manual.
  Wayne Woldt. University of Nebraska, Department
  of Biological Systems Engineering.
• 2. Ohio Department of Natural Resources- Division
  of Water Publications.
• http//www.dnr.state.oh.us
• 3. Memorial. University of Newfoundland.
  http//www.mun.ca